# \bqty

Used to surround a required expression with square brackets in the physics package, optionally with plain starred fences or explicit sizing prefixes.

https://texform.dev/latex/commands/bqty

## Metadata

| Field | Value |
| --- | --- |
| Topic | [Physics: quantities](https://texform.dev/latex/topics/physics-quantities) |
| Packages | physics |
| Allowed mode | math |
| Tags |  |
| Commonality | low |
| Kind | prefix |

## Syntax

### physics

Argument specification: `s m{}`

Used to surround a required expression with square brackets in the physics package, optionally with plain starred fences or explicit sizing prefixes.

## Examples

```latex
\bqty{a}
```

[Open in Playground](https://play.texform.dev/?input=%5Cbqty%7Ba%7D)

```latex
\bqty*{a}
```

[Open in Playground](https://play.texform.dev/?input=%5Cbqty*%7Ba%7D)

## Renderer support

| Package | MathJax | KaTeX | XeTeX |
| --- | --- | --- | --- |
| physics | full | none | full |

## In TeXForm

TeXForm parses this entry as prefix syntax; the package determines its argument specification.

### Expands to (physics)

```latex
\bqty{#1}
```

→

```latex
\left[ #1 \right]
```

With a leading star, the reparsed form uses plain fences `[ #1 ]`; with an adjacent sizing control sequence \big, \Big, \bigg, or \Bigg before the brace, it reparses to the corresponding sized fence form.

### [physics/bqty-to-bracket-fence](https://texform.dev/rules/physics/bqty-to-bracket-fence)

Rewrite bqty to explicit bracket fences.

Level: faithful. Fidelity: render.

```latex
\bqty{#1}
```

→

```latex
\left[ #1 \right]
```

```latex
\bqty{a+b}
```

→

```latex
\left[ a+b \right]
```

## Equivalent forms

```latex
\qty[#1]
```

exact. Both forms use the same delimiter semantics; \bqty packages the brackets as a brace-taking command.

## See also

- [\\abs](https://texform.dev/latex/commands/abs)
- [\\absolutevalue](https://texform.dev/latex/commands/absolutevalue)
- [\\Bqty](https://texform.dev/latex/commands/Bqty)
- [\\norm](https://texform.dev/latex/commands/norm)
- [\\order](https://texform.dev/latex/commands/order)
- [\\pqty](https://texform.dev/latex/commands/pqty)
- [\\qty](https://texform.dev/latex/commands/qty)
- [\\quantity](https://texform.dev/latex/commands/quantity)
- [\\vqty](https://texform.dev/latex/commands/vqty)

## Test cases

### physics

| Input | Case | MathJax | KaTeX | XeTeX |
| --- | --- | --- | --- | --- |
| \bqty{a} | Positive: baseline | Pass | Fail | Pass |
| \bqty*{a} | Positive: vary:s[0] | Pass | Fail | Pass |